1970 Chevelle Transmission Build - Our Hero Gets A Six Shooter

When the '10 Camaro hit the market earlier this year, one of the more interesting options was the new 6L80E auto transmission. Featuring six forward gears, the new transmission helped the Camaro earn top marks for fuel economy and drivability, but for the performance enthusiast has a few shortcomings that limit its potential, including the maniacal and sometimes frustrating torque management system that protects the transmission from abuse.

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With enthusiasts already looking at retrofitting the 6L80E into their classic Bow Ties, the transmission gurus at TCI decided there was a better way to put a six speed automatic in a classic Chevy. After looking at everything in the automatic stable, the decision was made to take the existing TCI 4L80E transmission and turn it into the new 6x six-speed automatic.
Since the 4L80E uses some of the same robust parts that the rock-solid Turbo 400 transmission employs, it was already up to the high horsepower applications TCI had in mind for the new six-speed automatic. An added bonus of using the 4L80 case is that it would fit in almost any transmission tunnel with no tunnel modifications necessary, so retrofitting one into an older Chevy would be no problem.

The 6x uses a 2.97 first gear, 2.23 second, 1.57 third, 1.18 fourth, 1.00 fifth, and .75 overdrive/sixth gear ratios, compared to the 6L80E's 4.02/2.36/1.53/1.15/.85/.66 gear ratio spread. The 6x also uses strengthened and improved internal gear sets, increased friction material, and other improvements that allow it to take high horsepower loads of over 850 hp. And because the 6x is fully electronic, it can use TCI's electronic steering wheel mounted paddle shift system for full manual shifting capability. In a test drive of a vehicle with a 6x, we were impressed by its smooth but firm shifting. The 6x can be electronically adjusted to personal shifting preferences.

To test out the TCI 6x on the street, I went for a spin in TCI's test mule, a 502 big-block-powered G-body Regal. Driving normally, the 6x shifted smoothly through all six gears, firmly but with no clunks or hard shifts normally associated with a performance transmission. Dropping the hammer, the 6x quickly upshifted, again smooth but firm without a neck snapping abruptness.
Thanks to TCI's transmission control unit, shift firmness, shift points, and other factors can be fully programmed to the driver's own desire. The optional TCI paddle shifter worked great when driving the car in "manual" mode, with no hesitation or lag when manually upshifting or downshifting the 6x. Going back and forth between manual and full auto mode on the 6x was also easy.

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